The present invention relates to hermetic terminal assemblies and more particularly to an improved insulating sleeve arrangement for conducting pins of a hermetic terminal assembly such as U.S. Pat. No. 4,296,275, issued to Benjamin Bowsky on Oct. 20, 1981; U.S. Pat. No. 4,461,925, issued to Benjamin Bowsky et al, on July 24, 1984; U.S. Pat. No, 4,580,003, issued to Benjamin Bowsky et al, on Apr. 1, 1986; and U.S. Pat. No. 4,584,433, issued to Benjamin Bowsky et al, on Apr. 22, 1986.
In the aforementioned patents at least one conducting pin is passed through a hole for such pin in the bottom of a cup-shaped body, with the hole being defined by an annular lip extending in the same direction as a rim of the cup-shaped body. A material is provided to seal the pin to the inner wall of the annular lip forming a sealing insulator therebetween; and a protective extension sleeve surrounding the pin is bonded to the sealing insulator.
In accordance with the present invention, it is recognized that prior art hermetic terminal assembly arrangements which have included a sealed, insulated conducting pin and protective ceramic extension sleeve adjacent thereto, on occasion have been encumbered with problems of sealing insulator cracking. It further is recognized by the present invention that such undesirable cracking often includes that area immediately adjacent the conducting pin with the cracking initiating where the protective ceramic extension sleeve contacts the annular lip and then migrating through the sealing insulator to the proximate conducting pin. This undesirable cracking has resulted in loss of electrical oversurface or leakage. Recognizing the cause and effect of these past undesirable cracking problems, the present invention provides a novel and unique hermetic terminal assembly which, in an efficient, straightforward and economical manner, serves to localize undesirable sealing insulator cracking, which might be brought about by sealing insulator, ceramic extension sleeve and annular lip contact, to an area remote from the sealed pin so as to minimize the risk of extensive reduction in electrical properties and concomitant loss of hermeticity. In addition, the present invention provides an improved, modified hermetic terminal assembly arrangement which not only provides for remote localization of such possible undesirable sealing insulator cracking but, in addition, provides an economical to manufacture and assemble extension sleeve of a universal nature with respect to the opposite ends thereof. Furthermore, the unique structure of the present invention accomplishes this in a straightforward, efficient and economical manner.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth hereinafter.